


Undercover in the Bunker

by spnsmile



Category: Supernatural
Genre: Angels, Angels are Dicks (Supernatural), Castiel and Dean Winchester Have a Profound Bond, Castiel and Dean Winchester are Dorks, Castiel and Dean Winchester are Saps, Castiel and Dean Winchester in Love, Castiel in the Men of Letters Bunker (Supernatural), Castiel/Dean Winchester in the Men of Letters Bunker, Challenge Response, Crack Treated Seriously, Cute, Domestic Bliss, Domestic Fluff, Domesticity in the Men of Letters Bunker (Supernatural), Established Castiel/Dean Winchester, Eventual Smut, Fluff and Crack, Fluff and Humor, Fluff in the Men of Letters Bunker (Supernatural), Guardian Angels, Idiots in Love, Jealous Castiel (Supernatural), Jealousy, Kissing, Love, M/M, Men of Letters Bunker (Supernatural), Neck Kissing, Romance, Sex in the Men of Letters Bunker (Supernatural), Sharing a Bed, Short & Sweet, Some Humor, True Love, Unexpected Visitors
Language: English
Status: Completed
Published: 2020-06-02
Updated: 2020-06-02
Packaged: 2021-03-04 05:15:27
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 1
Words: 3,525
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24508273
Author URL: https://archiveofourown.org/users/spnsmile/pseuds/spnsmile
Summary: Castiel invites an angel to the Bunker to 'observe' the Winchesters in order to change Heaven's view about his charge, only to end up making Dean just a little miserable and himself a little jealous.
Relationships: Castiel/Dean Winchester
Comments: 12
Kudos: 118





	Undercover in the Bunker

**Author's Note:**

> written for #spnStayAtHOme challenge with theme: Undercover
> 
> I enjoyed the crack ^^

When it becomes apparent the Winchesters cannot win against the all-powerful, and that they require more help from all Supernatural beings in order to defeat god, Castiel takes initiative to reach all forces, especially Heaven.

Taking the opportunity after giving Jack respite out of the Bunker to say with Kaia and Claire, Castiel fully focuses on getting the side of the angels. He didn’t expect it to be easy.

The angels do not want to have anything to do with the Winchesters, not by their ‘chinny-chin-chin’ as Dean once quoted for not opening Heaven’s door when their need was dire. But it’s not the chins the angels are most concerned about. There are some who think the written prophecy will still take place and as angels, they still adhere to ‘not interfering’ much to Castiel’s chagrin.

Not wanting to contradict them further, Castiel doesn’t stop trying to convince them that there is no reason to be wary of the Winchesters (as long as the intention is not to harm or Castiel will be in their way) for they will play a key role in fixing everything. And by fixing, he explains patiently it is not the destruction of god, but of something only the Winchesters are capable of doing— a _miracle._

Eyes and eyebrows turn and arches, but Castiel knows he’s able to sway some of them at his display of faith. If there’s anyone right at the top in faith, it would be them. One steps forward, his name is Sabrael, an angel of miracles.

“I do not wholly believe that the Winchesters are redeemable—” begins the golden-haired seraphim once he and Castiel jump out of the portal in the sandbox and head for Castiel’s car, “But I do believe their knack of pulling out miracles one after another is something to behold and I wish to understand why your faith is still with them after all these times given that they are the infamous brothers who brought forth the destruction of all realms. For that purpose, I will be amenable to let you show me why this is so and act as heaven’s representative to gather information from your charge.”

Castiel shrugs, unable to find any words to counter.

“So, you’re going undercover?”

Sabrael glances at him and squints, “Am I required to go under the Winchesters’ cover?”

Castiel blinks.

“Um… I am not sure what you mean by that but if it means protection, then yes.”

“I do not need their protection,” Sabrael says in all seriousness as they get in Castiel’s car. “I am capable of that; I have my angel blade.”

“It won’t be enough protection but, Sam and Dean are nice people and will readily be there for you whether you ask it or not…” Castiel smiles more to himself, thinking of the Winchesters’ selfless acts they never boast about.

“That’s how they… um… roll. They don’t ask, they just do. And most of the things they do are genuine to help others. They will help you out, they thrive in helping. They are very kind… well, mostly, Sam. Dean can be a little complicated with angels…”

“And he is your charge?” the tone is testing the waters.

“He is, but he is a very unequivocal man and very… very Dean. You have to have a profound relationship with him to understand him…”

“I understand you bonded with him in hell? That’s where it all began—”

Castiel stops only to turn a very solemn expression to his brother, “One thing in this mission, Sabrael. Do not intentionally say anything untoward about brothers. You can say anything you want about me, about I am one of the Fallen, about my failures, but… don’t ever insult Sam and Dean in my presence…”

His eyes are intent on Sabrael.

“They already have the world on their shoulders to receive unjust ridicule from our kind— it will be distasteful if we are ungrateful.”

“I am not grateful.” At Castiel’s livid face, Sabrael adds cautiously, “But as I have told you, I will be amenable. No matter how complicated you deem him to be… I will try my best to study him, keeping in mind he is still a special vessel meant for our brother.”

Castiel glares before revving the car.

It’s easy to make Sabrael understand for angels are obedient by nature. He explains about the Bunker where few angels are able to find, the hunting system and how some of the room works as the library, the kitchen, and the bedrooms, and to other places, a visitor will not be allowed entrance.

“I understand. It seems there are plenty of restrictions in this Bunker.” Sabrael says thoughtfully, “Is Dean Winchester’s cave so holy to put so many sigils of protection? Why are angels not allowed there if it is such a sanctuary?”

“Because it’s just is,” Castiel says distractedly, “… and it’s not holy.” He doesn’t explain further even when Sabrael keeps throwing him confused glances. “Anyways, just let me tell Dean why we’re doing this… he’ll understand… and please, don’t tell him directly you are an undercover agent from heaven. I’ll come up with a good explanation, trust me, they’ll never think of you as a threat...we’ll just tell him you’ll… observe the field.”

“You think he will not realize I’m there to spy?”

“You’re not a spy.”

_Because it’s really not like that._

“So, he’s a spy?” Dean says lazily from the library table with cheek propped up on his knuckle.

Castiel sighs in resignation. Beside him, Sabrael elbows him and says very clearly—

“You really don’t get this, huh?”

After a round-about story of how he invites the angel to see for himself how the is getting along with Sam and Dean—where Dean butts in about spying, Castiel informs the Winchester that Sabrael will be staying with them for as long as necessary and that if they could extend their hospitality to his brother as the Winchesters once did for him.

Sam smiles genuinely, “Of course, Cas… your family is our family.”

Dean ogles at Sam weirdly before he snorts, shaking his head.

“Fine, make yourself at home.”

Saying so, Sabrael walks to the table, to the chair adjacent to the hunter and takes his seat, leaning on the table too for good measure and he stares at Dean from pore to pore, making the hunter throw an incredulous look at his angel.

“What are you doing?” Dean asks, leaning a little away before he gets cross-eyed.

“I’m studying you.”

Dean glares at Castiel with one of his screaming expression of— ‘ _great-Cas-just-great’_ look while Sam chuckles—earning him another exasperated glare as well. “Fine, whatever.”

“You trust me easily,” Sabrael tells Dean quietly.

“I trust Cas,” Dean says simply, still glaring and flipping his book at the same time, “just make sure you don’t start shedding salty feathers around, we’ll be fine.”

“My feathers are not salty,” Sabrael says, indignantly.

“How d’you know? Wait, you actually lick it for grooming, eh? Do you spit _feather-hairballs_?” Dean grins at the scowl he receives.

Ten minutes later, Sabrael declared Dean Winchester to be rude and without consideration whatsoever. Castiel grimaces.

“Honestly, Castiel how can you endure an arrogant man who knows no bounds in insulting heavenly beings?”

“I just…stopped caring about the things he says,” Castiel shrugs.

“That is not very healthy. I find Sam Winchester more agreeable—and he is supposedly the vessel of the real devil while Dean Winchester is Michael’s—”

“I know, I have been in the exact train of thought.” Castiel says sympathetically, “But I wouldn’t… stress on it… Dean can be very… disagreeable at the beginning but once you warm up to him, you’ll see… he is a very caring guy.”

***

“Still here?” Dean says flatly when he comes to the kitchen the next morning and automatically road blocked by the new angel in the Bunker. Castiel couldn’t be more embarrassed remembering how he used to startle Dean in the same manner.

“I did say I will study you,” Sabrael says stubbornly.

“You can study my ass,” Dean tells Sabrael who blinks and lets his eyes travel down to Dean’s thighs and his behind, making Dean give Castiel a painful grimace.

Sam laughs. Castiel hung his head guiltily.

Days get busy in the Bunker and Sabrael is allowed to tag along. His angel brother doesn’t make it easy with side comments of how still ‘wasteful and bloody’ the Winchesters deal with some hunts that can be done without much bloodshed or getting thrown around to how Dean’s car is rickety and noisy, there’s no doubt in Castiel’s mind that Sabrael just made it to Dean’s top ‘Angel Douche’ of the year.

“Sammy, get me some angel proof spell!” The request was immediately denied when another day panned out with Castiel’s brother is found inside Dean’s room.

“Why don’t you angel proof it yourself?” Sam asks.

“What—you want Cas to face slapping the wall? Not that we’re not doing that already.”

“Ew! Dean! Don’t be gross over my salad!”

But Dean smiles sunnily and looks across at the angel by the entrance of the kitchen who comes back after a long talk with Sabrael. He tells him he cannot sneak inside Dean’s room no matter how much he wants to understand why Castiel is so enamored by the hunter—or why only Castiel is allowed entry.

It’s impossible to understand.

“Found out why he’s sticking in my ass?” Dean asks once the two of them are side by side and washing the dishes—Dean washing, Castiel wiping them dry.

“He wants to study our bond.”

“Why? He wants to bond with someone?”

“I’m not sure, but Sabrael is known for his persistence in his garrison.”

“Are you kid- someone else is more persistent than you are?” Castiel glares back as Dean smiles cheekily again but there’s a comfortable atmosphere that falls between them where Castiel is sure Sabrael is able to study.

* * *

Sabrael doesn’t care for space like the other angels before him.

To Dean’s credit, he barely flinched at the space taken but the occasional curses and grinding of teeth do get Castiel’s attention from time to time. It’s not much about Dean’s irritation and Castiel’s worry that he might explode—Dean will if he wants to and nothing can stop him—but every time he thinks Dean is about to erupt from what Sabrael said, (“This Dean-Cave is no Holy den nor is it any sacred as any cave, but just another dingy ditch”) Dean calms down.

Just one look at Castiel and Dean calms down. Two weeks passed and the routine gets old. Sabrael still cannot find it in him to see any delightful features on Dean Winchester who doesn’t bother trying to win Mr. Congeniality.

To be fair, Sabrael does not have a winning personality either.

“You know what for a spy—you’re not very spy-ish.” He tells the angel who walks pass him quietly.

“I don’t do ish, what is ish?” Sabrael wants to know.

Dean glares at Castiel so hard the angel of the Lord ends up rubbing the back of his neck nervously.

“I’m sorry about this,” he tells Dean one night when he stands at the foot of his friend’s bed with Dean busy folding his flannel and shirt.

“Can you smite him?” Dean asks without looking up.

“Dean,” Castiel admonishes lightly.

“Too bad, I was just thinking he’s growing fond of me,” Dean is very meticulous when it comes to the folding—much more than Sam. Castiel can attest how much Dean has been trained for it—he remembers Dean telling him how he has to take care of their laundry as children and about how he never wants Sam’s clothes wrinkled no matter how many fucking schools they transfer. He always wants Sam to look well-taken care because it’s what his genius brother deserves.

Castiel loves him for that.

“Here, let me—” he steps toward the bed but Dean presses two fingers on his forehead, much like how Castiel does when he could teleport them with his powers before. Castiel’s face falls. Dean smiles.

“I don’t want your brother hearing how I make you scream you know? Don’t want to add it to his long list of ‘Why I hate Dean Winchester’.”

“He doesn’t hate you.”

“Yeah? Do you know how he lectured me for eating beef while you took your sweet time taking care of the case with Sam in Maine? Or how he says pies tastes like ‘dung’. Son of a—does he only exist to insult my life?

“I’m sorry, Dean,”

“It’s not you, Cas, but how does he know? Your angel brothers make it a habit to taste shit cow pies? Ever had that in your life, Cas?”

“I’m just going to fold your shirt, what does it have to do with him?” Castiel frowns but he doesn’t push it.

But Dean’s eyes gleam darkly.

“Sure, my angel near my bed, inside my room, folding my shirts,” Dean gives him a playful smirk, “Kinda hot in my vocabulary but nah… I want your brother to play the gossip… about how we expanded the staring contest to something…sexy… But with a dude like that? I don’t think he’s the type to run back with tail between his legs once he finds out. He’ll be a buzzing fucking bee in my ear.”

Castiel leaves the room more disappointed than he expected. But all the same, he has to talk to Sabrael.

* * *

“Cas, what the hell?”

Sabrael’s face crumples in so much contempt, Castiel has to put a hand on his brother’s soldier to appease him and explain for full thirty minutes how it is not as offensive as it sounds.

It’s at this that he receives an equally critical look from his brother.

“You are letting them treat you this way? You—the angel of the Lord, warrior, and Commander—”

“Yes.” Castiel says without qualms, “Because we are family.”

“I have watched families over and over in this world and yes… this may be what they call a little dysfunctional. But for you to allow it…”

“I won’t ask you to submit to it but, if it makes you feel better—I call Dean stupid all the time.”

Sabrael takes the cue from that so the next day when he is about inches from Dean’s face again, he says, “So, you are stupid.”

Castiel drops the book he is reading from the library as he hears the conversation. He can tell Dean and Sabrael are in the kitchen—clashing early that morning so he hurries towards them.

“Don’t,” Dean growls with eyes of steel intent on his target, “that’s a pet name we have so don’t go throwing it around careless.”

Sabrael flairs in anger.

_“You think Castiel is your pet!?”_

“N-no, that’s not what—I like Cas okay? He belongs with me,”

“You are establishing ownership like he is no more than your pet.”

“ _Dammit, stop twisting my words_! I don’t care how you interpret that, he’s mine! Cas belongs to me!”

“You’re right, I do not belong here,” there’s bitterness lacing Sabrael’s words. Castiel stops at the threshold, listening in, hoping his brother and Dean don’t end up any more quarrelsome than they already are.

There’s a beat. He hears Dean grumble under his breath.

“Of course, you do,” Dean says, “you’re an angel-like Cas, angels belong in my world. I don’t want to exist where you don’t so you belong right here in this space, okay? Angels belong to me so by extension—you belong in my world too, you little childish spy.”

Castiel smiles as he leaves the wall and walks quietly to the corridor. He realizes it will start from here on, of how Sabrael will see how special Dean Winchester really is. He doesn’t see the way Sabrael’s eyes light at Dean’s words, doesn’t see the abrupt change of his expression, and the slight blushing of his usually pale cheeks.

All he knows is that his brother has glimpsed the burning soul of the man he vows to protect and love.

_Oh, his word._

* * *

“C-CASSSS!” Dean shouts at the top of his lungs—and it’s not the ‘serious-facing-instant-death’ kind, in fact, it sounds like one of Dean’s cries whenever he sees a cat or anything ridiculous for the angel’s eyes—and yet that Dean is screaming from the comfort of his room is wrong. Castiel nearly destroys the door of Dean’s room when he crashes it open—

That’s where he finds Dean Winchester with back plastered on the headboard of the bed and Sabrael under Dean’s covers with only his head seen from underneath.

Sam comes in to check and when he sees everything, he leaves the corridor and forsaken his brother to the two angels while Castiel marches in with a dark expression and, from Dean’s description later, ‘ _goes in and kick an angel’s butt’._

Castiel doesn’t need any long discussion with Sabrael. The angel has learned of the magic of Dean Winchester and that’s enough. Sabrael doesn’t need to say it, Castiel can see it the way his brother’s eyes light up when he sees Dean. Castiel actually likes the change, of the angels loving his charge… as long as they do not step on the line.

But it is time to say goodbye.

“You are not bad, Dean Winchester. And I wish to be under the same covers as you again for you are warm… warmer than this vessel.”

Dean blushes whereas Castiel throws him a glowering look. To Sabrael, he raises one heavenly dominant eyebrow that strikes friends or foe.

“I think your undercover game is over,”

Sabrael stares back, somewhat crestfallen.

“But I want—”

Castiel grimaces and shakes his head. “No.”

_Not going to happen._

To Castiel’s annoyance, Sabrael exchanges a pleading look with Dean. The hunter blinks several times and Castiel can just see Dean’s defenses of forgiveness even after being attacked in his own bed because Dean is kind like that, always forgiving, always with the generous heart even when he is wronged.

“No,” he repeats when Dean opens his mouth and they gaze at each other. With brief excuses and apologies, Sabrael wraps his business with the Winchesters and Castiel escorts him back to the sandbox in silence.

But when they reach heaven’s door, Sabrael turns to Castiel with a small smile.

“I now understand, brother. Why you choose to be with him,”

Digging his hands deep inside his trench coat pockets, Castiel nods without needing to clarify and Sabrael returns back to heaven with a final longing expression in his face.

Castiel never wants to have the same expression of regret.

Returning to the Bunker late that night, he knocks at Dean’s door, opens it to see Dean reading a book quietly on his bed under the night lamp, covers drape his middle and ambiance so familiar and comely that makes Castiel want to wrap himself in Dean’s warm space because Sabrael is right in all aspects of Dean.

“You’re never the jealous type, Cas,” Dean says as Castiel sheds his coat and crawls on the bed towards him, Dean pulling his necktie to get him close enough for a soft kiss.

“Not really. I have my own type.”

“The type that pulls other angels from my lap?”

“Yes, this lap is mine,” saying so he pulls the covers from Dean and straddles his lap. They smile and kiss, Castiel wrapping his arms around the hunter’s neck while Dean runs his palms on Castiel’s side. When they pull from the long, lips-chasing-catching-kiss, Dean narrows his eyes at him.

“What’s this about being under my covers? You talk to the angels about our business?”

“The family business?”

“No, our dirty bedroom business.”

“Your bedroom is never dirty,” Castiel lets Dean unbutton his shirt, letting the loose tie hang around his collar still, “You have the neatest room I have visited in my long existence,”

Dean frowns, “Exactly how many bedrooms have you visited… and do you—you know—do the same—"

“Do not be stupid, you’re the only man I engaged with.”

Dean kisses his neck as the dress falls down his shoulders. They remove all the extra layers until they are both warm skin to skin. Dean loves suckling his earlobes, making Castiel’s breath hitch a little.

“And women?” Dean whispers. Castiel clutches on his shoulder for support. Dean’s mouth on his skin sends fiery flames all over his vessel.

“My body… has been rebuilt many times— it doesn’t count.”

“Oh, so every time you return… ah…” Dean’s eyes dance in mischief, “that’s why you’re always so tight.”

Castiel pecks on Dean’s pink cheek, engrossed by the way Dean is smiling so happily. He can’t help himself. He kisses Dean. The hunter pushes him down the bed and stays on top of him, smiling from ear to ear and Castiel believes he does belong with Dean. That there is no universe he can be without a Dean.

“Loosen me.” He says.

Dean laughs as he throws the covers over their heated, tangled bodies.

_“As you wish.”_

**Author's Note:**

> Stay safe everyone!


End file.
